Resize line by mouse

[alan.dodd]

Hello.
In your demo 'Editor' after I load a dwg I can select a line by clicking on it, and then I can drag it around.
1) How can I change its length with mouse? I want to click one end of the line and drag only that end, so I can make the line shorter or longer, and also change its orientation.
2) I need to see the line changing as i move the mouse, not just when i release the mouse button.
3) I need same thing for a polyline (e.g. rectangle to be able to stretch it in x and y directions)
Thank you.